Vulnerability · Published Nov 5, 2026 · Assigned by mitre
CVE-2026-107891
High 8.1
In plain English
A high-severity integer overflow in musl from musl -libc. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.5%top 53.9% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
musl libc before 1.2.7, when an untrusted regular expression is used with regcomp, has multiple integer overflows, possibly leading to incorrect allocation sizes and out-of-bounds heap writes.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | musl | 1.2.5-r4 | ALPINE-CVE-2026-107891 |
| Alpine:v3.21 | musl | 1.2.5-r12 | ALPINE-CVE-2026-107891 |
| Alpine:v3.22 | musl | 1.2.5-r13 | ALPINE-CVE-2026-107891 |
| Alpine:v3.23 | musl | 1.2.5-r24 | ALPINE-CVE-2026-107891 |
| Alpine:v3.24 | musl | 1.2.6-r3 | ALPINE-CVE-2026-107891 |
| Debian:12 | musl | no fix listed | DEBIAN-CVE-2026-107891 |
| Debian:13 | musl | no fix listed | DEBIAN-CVE-2026-107891 |
| Debian:14 | musl | 1.2.6-2 | DEBIAN-CVE-2026-107891 |
| Ubuntu:22.04:LTS | musl | no fix listed | UBUNTU-CVE-2026-107891 |
| Ubuntu:24.04:LTS | musl | no fix listed | UBUNTU-CVE-2026-107891 |
| Ubuntu:26.04:LTS | musl | no fix listed | UBUNTU-CVE-2026-107891 |
| Ubuntu:26.10 | musl | no fix listed | UBUNTU-CVE-2026-107891 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| musl -libc | musl | 0.5.0 – before 1.2.7 |
Weakness: CWE-190 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H